Trolley conveyor track systems are widely used in department stores, warehouses, factories and a wide range of other business and industrial activities for the purpose of transporting stock, parts and broad classes of goods between central collecting and distributing stations and remote stations. Systems of this type employ a main track which can have a number of sections and various branch track sections which make juncture with the main track at a switching station. The switching station usually includes a switch rail unit which is adapted in one switching position for connecting together two sections of the main track while in a second switching position, the switch rail unit connects a main rail track section with a branch track. With respect to monorail-type conveyor track systems, it has been commonplace heretofore to provide the switch rail as a flexible rail member such as either a coil spring or length of resilient material or as a rail member of two rigid components connected to each other at a universal joint. In such fashion, the switch rail is designed to assume a bent, arcuate or curved position when it is moved to a position for connecting the main track to a branch track. In respect of such switch rails as are provided in the form of rigid members joined by universal joint connection, the same offers the drawback that too often, a trolley traversing the turn thereon between the main track and a branch track, is derailed since it cannot negotiate properly the single point turn structure at the juncture of the rigid members. Flexible rail sections, as heretofore used in the art, e.g., as exemplified in U.S. Pat. No. 3,605,628, while sufficiently flexible to provide a smooth curving and in effect plural point track switch course, have the disadvantage that the flexible member deflects under the weight of the trolley and load with such flexure offering resistance to continued travel, i.e., such condition can undesirably slow or even stop the trolley.
Accordingly, it is desirable that an improved switch rail unit be provided for such trolley conveyor track systems which unit not only provides a smooth curving track course but regardless of the switching position thereof will not be subjected to undesirable flexure, particularly such flexure as tends to depress the switch rail below the horizontal plane of alignment of the respective track sections.